Microfluidics relates to the behavior, control, and manipulation of fluids that are geometrically constrained to a small, typically sub-millimeter, scale at which capillary penetration governs mass transport. Microfluidic devices to control fluid movement, which include micropumps and microvalves, can be constructed using various fabrication techniques and have various applications in the environmental, medical, biotechnical, printing, analytical instrumentation, and miniature cooling industries. Microvalves, however, cannot simply be constructed as scaled down versions of macrovalves of larger dimensions, as the components included within the microvalve are not practically or economically scalable. Accordingly, what is needed is a microfluidic control apparatus or device, in particular that may be used to control or relieve pressure within microfluidic fluid applications.